Understanding the “Dawn Phenomenon”

Patients who manage morning blood sugar highs can better control diabetes

DAYTON, Ohio (November 13, 2018) – In the early morning hours before we wake up, our bodies produce a surge of hormones that increases the level of glucose in the blood.

The body’s normal response to this “dawn phenomenon” is a release of insulin to lower and control blood sugar levels, but people with diabetes struggle to maintain this balance because the body doesn’t produce the insulin it needs, according to the American Diabetes Association (ADA).

“As those hormones peak, insulin peaks and we can control our blood sugar in a very normal, steady level,” said Miguel Parilo, MD, a diabetologist with Bull Family Diabetes Center.  “In someone with diabetes, the result is an abnormal elevation of blood sugar in the early morning hours.”

Most people with diabetes don’t feel any symptoms of a dawn phenomenon. Instead, they notice elevated blood sugar levels when they take a fasting blood glucose reading.

“The real feeling is of frustration because a person is trying to do the right thing in taking their medicines and eating properly,” said Dr. Parilo, who practices with Premier Physician Network.

“When this happens, patients should work closely with their doctor to determine what’s truly causing the high fasting blood glucose levels and what can be done to correct the problem,” said Mark Williams, MD, a primary care physician with Jamestown Family Medicine.

Dr. Williams said many factors cause elevated blood sugar in the morning hours, such as stress, consumption of carbohydrates at night, and ineffective medication. It can also be caused by the Somogyi effect - when the body compensates on its own for low blood sugar levels by boosting glucose levels to rebound, causing high morning blood sugar.

Our levels of growth hormone, cortisol, adrenalin and other hormones tend to rise between 2 a.m. and 3 a.m. and begin to taper off between 6 a.m. and 8 a.m. People with diabetes see a rise in blood sugar during this time because their bodies make less insulin and more glucagon, a hormone that increases blood glucose, the ADA said.

“We have very little ability to influence our hormone levels,” said Dr. Parilo. “But we can make positive changes to prevent blood sugar from rising.”

Drs. Parilo and Williams recommend these steps to reduce fasting blood glucose levels:

Eat fewer carbs – What and when you eat impacts your early morning blood glucose levels. When you eat a low-carb supper earlier in the day, you avoid adding to the high blood sugar levels that occur during the dawn phenomenon. Working with a registered dietician can help assess your nutritional needs.

Limit nighttime snacking – If you get hungry close to bedtime, choose snacks that won’t increase your blood sugar, such as cheese, nuts or eggs.

Exercise – Be active, especially after dinner. Exercise can reduce blood glucose levels throughout the night. Try walking, yoga or bike riding.

Reduce morning carbs – Assess what you eat for breakfast and plan meals low in carbohydrates. Be sure to account for all carbs, including those in coffee creamers and those in a healthy meal.

Check your medications – If you take insulin, make sure you are getting the right type of insulin in the right amount, at the right time of day. Talk with your doctor to determine if the medicines you use are working as they should. An insulin pump can tailor insulin delivery to the minute to control blood sugar during the sleeping hours.

If you’ve made changes to your diet and medicines and still experience high blood glucose levels in the morning, Dr. Parilo said using a continuous blood glucose monitor can pinpoint when blood sugars peak and fall throughout the day. 

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